We spoke last night and it turns out he did not feel the "block" so much any more but has a low sex drive, and has had for years. First, I was devastated and sobbed for an hour, thinking this was the end. But then, he apologized for not telling me this and (if a bit reluctantly) agreed to see if there was anything he could do to increase his drive. And we both promised to get better at sharing feelings and thoughts on the subject and in general.
It was not the answer I expected or wanted. But now that I know what's going on I feel that I can cope with it and not get so upset and disappointed when I don't get any. I also told him that he could be rougher with me during sessions, (He's been quite careful and easy with me since a drunken session turned bad) and he was very happy with that. I find playing and aftercare very intimate and can replace that part of sex.
So even if this is not the optimal situation, it feels a lot better knowing what's going on. Communication is, apparently still, king.
Thank you!